1. Field of the Invention
This invention relates to an image processing apparatus, and more particularly is directed to such an apparatus that can create a pseudo three-dimensional image by adding a Z value to two-dimensional image data.
2. Description of the Prior Art
An arbitrary figure PT 10, as shown in FIGS. 1 and 2, is represented by image data that consists of two-dimensional coordinates defined with respect to X and Y axes and that has no Z axis coordinate data. Such image data cannot easily be combined with image data defined by three-dimensional coordinates.
For example, FIG. 3 schematically illustrates image data PT 12 defined by two-dimensional coordinates and image data PT 13 defined by three-dimensional coordinates. When it is intended to display together images represented both by the data PT 12 and the data PT 13, the data that can accurately be displayed in two dimensions is determined by the order in which the respective image data PT 12 and PT 13 is written in memory. Accordingly, in order to combine image data defined by two-dimensional coordinates with image data defined by three-dimensional coordinates, it is necessary to add Z coordinate data to the image data defined by two-dimensional coordinates.
It is known to calculate such Z coordinate data by means of a processor operating under software control and then to add the calculated Z coordinate data to the two-dimensional image data. However, such calculation of Z coordinate data requires an undesirably long period of time.